CEM 200 1st Quiz

First civilization recognized to use concrete

Mesopotamia

Aesthetic effects of concrete

A recognized non-mechanical characteristic and architectural advantage of concrete.

Elastic behavior

An instantaneous response to an applied load in which the material fully returns to its original dimensions upon unloading.

Elastic limit (in concrete stress-strain)

The threshold below which material deforms without cracking; exceeding it initiates cracking and structural failure.

Portland Cement Concrete (PCC)

A composite material made of filler (coarse aggregate and fine aggregate) and binder (Portland cement, water, and admixtures).

Paste (binder)

The mixture consisting solely of Portland cement, water, and admixtures.

Mortar

A binding mixture consisting of cement, water, admixtures, and fine aggregate (FA).

Grout

A high-fluidity mixture of cement, admixtures, approximately twice the standard mixing water, and fine aggregate (or no aggregate) with small coarse aggregate.

Admixtures

Chemical substances added to a concrete mixture to modify and improve specific fresh or hardened properties.

Hydration (concrete)

An exothermic chemical reaction between water and cement particles that forms new bonding compounds and continuously strengthens the matrix.

Optimum water-cement ($\text{W/C}$) ratio range

$0.50$ to $0.55$

Water-Cement ($\text{W/C}$) Ratio Law

The principle that compressive strength, durability, and density are inversely proportional to the ratio of water to cement.

Calcareous raw material in Portland cement

Limestone, chalk, or oyster shells supplying Calcium Oxide ($CaO$), making up approximately $75\%$ of primary raw materials.

Argillaceous raw material in Portland cement

Clay, shale, or blast furnace slag providing silica, alumina, and iron oxide, making up approximately $25\%$ of primary raw materials.

ASTM Type I cement

Normal, general-purpose Portland cement used for standard construction applications.

ASTM Type II cement

Moderate sulfate-resistant cement with moderate heat of hydration.

ASTM Type III cement

High early-strength cement designed for rapid hardening.

ASTM Type IV cement

Low heat-of-hydration cement used in massive structures such as dams to prevent thermal cracking.

ASTM Type V cement

High sulfate-resistant cement designed for severe exposure to aggressive soils and groundwater.

Slump test

A standard field test used to determine the workability and consistency of fresh concrete.

Target slump range for standard fresh concrete

$3\text{ in}$ to $6\text{ in}$

Bleeding (fresh concrete)

A segregation defect where internal mix water migrates upward and pools on the surface.

Entrained air

Microscopic, intentionally generated air bubbles distributed uniformly to increase resistance to freeze-thaw cycles.

Entrapped air

Unintentional, irregular void spaces that decrease concrete density and mechanical strength.

ASTM C39

The standard test method for determining the compressive strength of cylindrical concrete specimens.

Standard design benchmark age for concrete compressive strength

$$28\text{ days}$$

Splitting tensile strength ratio

Approximately $\frac{1}{10}$ of the compressive strength of the concrete.